Kernel: All processors use LAPIC timer when running with APIC

This makes scheduler preemption much cleaner as bsb does not have to
send smp messages to notify other processes about timer interrupt.

Also PIT percision is now "full" 0.8 us instead of 1 ms that I was using
before.

kernel/kernel/kernel.cpp

@@ -1,4 +1,5 @@
 #include <kernel/ACPI/ACPI.h>
+#include <kernel/APIC.h>
 #include <kernel/Arch.h>
 #include <kernel/BootInfo.h>
 #include <kernel/Debug.h>
@@ -167,6 +168,12 @@ extern "C" void kernel_main(uint32_t boot_magic, uint32_t boot_info)
 	Random::initialize();
 	dprintln("RNG initialized");
 
+	if (InterruptController::get().is_using_apic())
+	{
+		SystemTimer::get().dont_invoke_scheduler();
+		static_cast<APIC&>(InterruptController::get()).initialize_timer();
+	}
+
 	Processor::wait_until_processors_ready();
 	MUST(Processor::scheduler().initialize());